GM said the trucks' transfer case "may electronically switch to neutral without input from the driver." If the problem happens while the truck is in motion, "the customer would experience loss of motive power," GM said in a separate notice to dealers.
If the truck is stopped or parked, it could roll away if the parking brake isn't set. GM said it isn't aware of related crashes or injuries.
Dealers will reprogram the transfer case control module, GM said.
GM also disclosed two smaller recalls: 4,794 Chevy Caprice police cars and SS sports sedans to repair a problem with the windshield wiper module assembly that could cause the wipers to stop working; and 1,919 units of the 2014 Corvette with the FE1 or FE3 suspension to repair a possible "insufficient weld in the rear shocks that could lead to a fracture an/or reduce the shocks' service life," GM said.
The recalls raise GM's total count for the year to 48 callbacks, covering about 20.5 million vehicles globally. Some of those are counted more than once because they've been called back for multiple recall-related repairs.
GM CEO Mary Barra reiterated in a TV interview this week that more recalls were likely. GM officials have said they are accelerating their review of older, lingering problems while more closely scrutinizing potential trouble with new vehicles.